mysql> ? contents
You asked for help about help category: "Contents"
For more information, type 'help <item>', where <item> is one of the following
categories:
   Account Management
   Administration
   Compound Statements
   Data Definition
   Data Manipulation
   Data Types
   Functions
   Functions and Modifiers for Use with GROUP BY
   Geographic Features
。。。

查看自己感兴趣的分类
mysql> ? Data Types
You asked for help about help category: "Data Types"
For more information, type 'help <item>', where <item> is one of the following
topics:
   AUTO_INCREMENT
   BIGINT
   BINARY
   BIT
   BLOB
   BLOB DATA TYPE
   BOOLEAN
 。。。

进一步查看具体的数据类型
mysql> ? int
Name: 'INT'
Description:
INT[(M)] [UNSIGNED] [ZEROFILL]

A normal-size integer. The signed range is -2147483648 to 2147483647.
The unsigned range is 0 to 4294967295.

URL: http://dev.mysql.com/doc/refman/5.5/en/numeric-type-overview.html

快速查阅某项语法是，可以使用关键字进行快速查询，例如，show命令
mysql> ? show
Name: 'SHOW'
Description:
SHOW has many forms that provide information about databases, tables,
columns, or status information about the server. This section describes
those following:

SHOW AUTHORS
SHOW {BINARY | MASTER} LOGS
SHOW BINLOG EVENTS [IN 'log_name'] [FROM pos] [LIMIT [offset,] row_count]
SHOW CHARACTER SET [like_or_where]
SHOW COLLATION [like_or_where]
SHOW [FULL] COLUMNS FROM tbl_name [FROM db_name] [like_or_where]
。。。

create table命令
mysql> ? create table
Name: 'CREATE TABLE'
Description:
Syntax:
CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    (create_definition,...)
    [table_options]
    [partition_options]

CREATE [TEMPORARY] TABLE [IF NOT EXISTS] tbl_name
    [(create_definition,...)]
    [table_options]
    [partition_options]
    select_statement
 。。。